link.exe: don't embed full path to PDB file in binary.

Author: michaelwoerister

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -929,6 +929,15 @@ impl<'a> Linker for MsvcLinker<'a> {
  // from the CodeView line tables in the object files.
  self.cmd.arg("/DEBUG");
 
+ // Default to emitting only the file name of the PDB file into
+ // the binary instead of the full path. Emitting the full path
+ // may leak private information (such as user names).
+ // See https://github.com/rust-lang/rust/issues/87825.
+ //
+ // This default behavior can be overridden by explicitly passing
+ // `-Clink-arg=/PDBALTPATH:...` to rustc.
+ self.cmd.arg("/PDBALTPATH:%_PDB%");
+
  // This will cause the Microsoft linker to embed .natvis info into the PDB file
  let natvis_dir_path = self.sess.sysroot.join("lib\\rustlib\\etc");
  if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) {

tests/run-make/pdb-alt-path/Makefile

@@ -0,0 +1,20 @@
+include ../tools.mk
+
+# only-windows-msvc
+
+all:
+# Test that we don't have the full path to the PDB file in the binary
+$(RUSTC) main.rs -g --crate-name my_crate_name --crate-type bin
+$(CGREP) "my_crate_name.pdb" < $(TMPDIR)/my_crate_name.exe
+$(CGREP) -v "\\my_crate_name.pdb" < $(TMPDIR)/my_crate_name.exe
+
+# Test that backtraces still can find debuginfo by checking that they contain symbol names and
+# source locations.
+RUST_BACKTRACE="full" $(TMPDIR)/my_crate_name.exe &> $(TMPDIR)/backtrace.txt || exit 0
+$(CGREP) "my_crate_name::main" < $(TMPDIR)/backtrace.txt
+$(CGREP) "pdb-alt-path\\main.rs:2" < $(TMPDIR)/backtrace.txt
+
+# Test that explicitly passed `-Clink-arg=/PDBALTPATH:...` is respected
+$(RUSTC) main.rs -g --crate-name my_crate_name --crate-type bin -Clink-arg=/PDBALTPATH:abcdefg.pdb
+$(CGREP) "abcdefg.pdb" < $(TMPDIR)/my_crate_name.exe
+$(CGREP) -v "my_crate_name.pdb" < $(TMPDIR)/my_crate_name.exe

tests/run-make/pdb-alt-path/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+ panic!("backtrace please");
+}